Modern Bush Regeneration
Regeneration is “The practice of restoring bushland by reinstating and reinforcing the systems’ natural regeneration processes”. The aim is to restore and maintain ecosystem health by helping the natural regeneration of indigenous plants.
The Bradley Method
In the early 1960s, through trial and error, Joan and Eileen Bradley developed a series of weed control and native vegetation recovery techniques known as the ‘Bradley method’. The method involves methodically clearing small areas in and around healthy native vegetation so that each area is re-colonised by the regeneration of native plants, replacing the weeds. The process showed that, once native vegetation was re-established, continuing weed control was needed infrequently.
The Bradley Method is a simple and adaptable approach to bush regeneration that is based on helping the bush to help itself. The benefits are long-lasting, and it works for both small and large areas.
The Bradley Method follows 3 main principles:
- Work outward from less infested to more seriously infested areas – these are the easiest to work with and have the best results
- Minimise disturbance to the site – in particular disturb the soil as little as possible and replace leaf litter following weed removal to discourage weed regrowth
- Don’t over clear – don’t treat too large, allowing native plants to germinate and regrow before proceeding to the next area.
Selected hand-tools were the only weeding tools used.Joan’s careful notes of Bush Regeneration were revised and 10 years after Eileen’s death and 5 years after Joan passed, “Bringing Back the Bush: The Bradley Method of Bush Regeneration (1988) was published.
The essence of these principles guides modern bush regeneration today, taking into account modern techniques and the need for appropriate ecological disturbance to trigger regeneration.
Development of National Standards in Ecological Restoration
There has been an evolution in thinking with a growing knowledge of the complexity of ecosystems and we now have the National Standards for Ecological Restoration Restoration in Australia.
The Ecological Restoration industry has grown and evolved, however the core principle of ‘work from the good areas out’ stands strong. There are many good reasons for commencing weed removal in areas of bushland where weeds are sparser before moving gradually into areas of denser infestation:
- The work is completed much faster where there is less to do
- The ability to cover the greatest area with the least amount of effort/resources
- Prevent good areas going backwards
- Natural regeneration is more likely in higher quality areas
- Level of maintenance (follow up) required is often very low
- Secure your good areas first, then you can move into other zones
- It decreases overwhelm
Principle 1 of the National Standards is to “Determine your Reference Ecosystem – this will inform the quality of your site and your goals”. There is little point treating areas that are low in weed cover if they are low in indigenous cover and diversity. Good areas are not just low in weed cover, but also have adequate indigenous species cover and higher biodiversity (no. of species).
The “good areas” will have three distinct features:
- Low weed presence or cover – measured as % cover
- High indigenous plant presence or cover
- High indigenous plant diversity – areas of high biodiversity
These areas are more resilient. Check for site resilience by comparing an area to the corresponding local EVC.
The Soil Seed Bank
Regeneration is the process of allowing an ecosystem to recover through the natural growth and recruitment of native plant species, without or with human intervention. It relies on existing seed banks, rootstocks, or nearby vegetation to re-establish biodiversity and ecosystem function.
The presence of a remnant soil seed bank that has not been damaged or destroyed indicates that a site has resilience or potential for regeneration. Intact seed banks have not been dug up, dumped on or destroyed.
All ecological restoration outcomes occur as a result of understanding and working with the soil seed bank. The condition of the soil seed bank will dictate the level of resilience and subsequent regeneration potential a site or area has, as the majority of natural regeneration occurs via the soil seed bank (small amounts occur from migratory seed).
Understanding the soil seed bank (including weed seed) is critical for developing effective strategies for ecosystem restoration and management. By manipulating the soil seed bank, we can promote the establishment of desirable plant species and help to restore damaged ecosystems.
The Role of Appropriate Disturbance
Since the 1990’s, rather than ‘minimal disturbance’, a more favoured and ecologically sound trend has leaned toward more ‘appropriate disturbance’, as many Australian plant communities require some level of disturbance to trigger germination from long-buried seed banks.
There are two types of disturbance:
- Anthropogenic (human induced)
- Evolutionary (mechanisms of regeneration)